Preventive effects of progesterone against neuropathic pain responses in a rat model of chronic constriction injury

Neuropathic pain is a chronic pain that results from damage to the central nervous system and also environment. Neuropathic pain is important for general health and approximately 6% of the adult population is affected worldwide. Despite the therapeutic choices, treatment for neuropathic pain is facing challenges. An experimental model that is very close to human neuropathic model is the chronic constriction injury (CCI) model. Progesterone (PROG) is one of the most potent anti-inflammatory and anti-inflammatory neurostimulants, and GABA-A receptor palys an important role in mediating the biological effects of PROG. In this study, the effects of PROG on behavioral responses of pain in the neuropathic pain model of CCI, and the possible role of GABA-A receptor in its effect were investigated in rats. 70 male Wistar rats were used in 7 groups (n = 10). First, neuropathic pain was induced by the CCI method in the respective groups. Following CCI, PROG (6 mg/kg) and or the GABA-A receptor antagonist bicuculin (0.5 or 2 mg/kg) or vehicle were administered daily until day 13 post-CCI. On days 14 and 27, the behavioural tests including mechanical allodynia and thermal hyperalgesia were done. Daily injections of PROG PROG for 12 days prevented the mechanical allodynia and thermal hyperalgesia following CCI and this effect was blocked the bicuculin pretreatment. The findings of this study showed that treatment with progesterone may prevent the development of peripheral neuropathy, at least in part, via GABA-A receptors.